1. Field of the Invention
The present invention relates generally to methods for performing pen-based computing, and in particular, to a method and apparatus for grouping and manipulating ink stroke representations. Still more particularly, the present invention relates to a note taking system that provides for simplified user manipulation of handwritten and printed ink strokes as characters and words in a word-processing system as well as the improved manipulation of other ink strokes as graphical images as in computer drawing programs.
2. Description of Related Art
Pen-based computers in which the pen replaces the keyboard as the primary input device have become well known. Such systems provide a digitizing pad and pen for the user to input information. The information is input in the form of strokes or graphic representations of strokes. The computer monitors the movement of the pen and creates a stroke when the pen comes within a pre-defined proximity or contact of the digitizing pad. The computer follows the movement of the pen across the digitizing pad while simultaneously extending the stroke, and ends the stroke when the pen is removed or moved away from the digitizing pad.
While programs have been created for converting pen-based input into characters, they are limited because they typically can only covert the input when the characters are written in distinctly separated boxes or positions. One of the continuing problems has been how to divide the input where the user enters several strokes just as if he/she were writing upon a blank sheet of paper. In fact, existing systems only store the ink strokes, and do not allow the user to perform editing tasks upon the ink images. There is no grouping of the ink strokes by paragraph and/or word to allow the user to perform standard word-processing functions. For example, there is no word wrapping (a common feature in word-processing programs) for the ink images.
One of the major problems in processing ink strokes is that there are a variety of writing styles. This makes differentiating between words, lines and paragraphs extremely difficult. Most computers do not separate ink strokes into words because the spacing between characters can vary greatly depending on the writing style of the person inputting the data. Existing computers are not able to separate lines of ink written data because with handwriting and printing there are several characters that are written below a line such as the characters "j", "y", and "g". Additionally, users are not precise in writing in a strict horizontal direction between lines. Finally, unlike systems with keyboards, there is no return or enter key. Thus, there is no demarcation by user when paragraphs are ending and beginning. Therefore, there is a need for a system that can be used with pen-based computers to provide the full functionality of word-processing programs on graphical representations of handwriting.
Another problem with existing pen-based computing systems is the ability to use word-processing functionality and drawing/graphic functionality interchangeably. When pen and paper are used for the drawing of figures or for the writing (or printing) of text, the user switches between drawing and writing operations seamlessly. However, in both keyboard-based computers and pen-based computers, the user must typically switch between application programs. This often entails entering several keystrokes or commands to switch the computer between modes of operation. This becomes very burdensome because pen-based computers are intended to be used in environments where the user often switches been drawing operations and word-processing operations hundreds of times per document. An added problem is that since the drawing and word-processing are two different applications, they also have different user interfaces, and thus, different formats for commands. Thus, there is a need for a system that integrates the word-processing and drawing functions into a single application.
Yet another shortcoming of existing pen-based computer systems, and computer drawing packages generally, is that it is very difficult to manipulate figures presented on the display. For example, most graphic/drawing packages provide a very narrow definition of the types of figures that may be considered as line types. Therefore, most figures are restricted to the more limited operations that can be performed on shape types, as opposed to the more appropriate operations performed on line types. Another problem with the prior art is that certain operations such as rotation of a figure are not built into the user interface to make them easily accessible, but can be accessed only by marking and then selecting the operation with specialized tools. This significantly limits the efficiency for the user. Therefore, there is a need for a note taking system that avoids the complications and restrictions of the prior are by providing integrated word-processing functionality and graphic/drawing functionality, and a system that is specifically designed for the pen-based computer environment.